Typically, Gmail inserts Unsubscribe next to the Sender's name. The word is clickable. If clicked, then Gmail sends an Unsubscribe request to the Sender.

By U.S. Law, emails originating in the U.S. from any type of Mailing List (shopping, association, membership, etc.) must include an option to Unsubscribe somewhere in email. Most often, you can find it in the small print after someone's signature.

If the Unsubscribe option is not listed near the Sender's name, Gmail offers the option to Block the Sender. Future emails from that Sender are then automatically sent to Spam.

Block can be found in the More Menu (3 dots) while the email is open.

NOTE:
If the Sender seems suspicious, it's best to Block the email instead of using the Unsubscribe link. Sometimes, that link may lead to a malicious website.

When accessing the Gmail app on a Smartphone, the options to Unsubscribe, Block or Mark as Spam are in the More Menu (3 dots).

Block or unsubscribe from emails

No.

As of 2020, Gmail does not offer a Safe Sender option. The best alternative options are:

• Add the Sender to your Contacts. Their emails will not be sent to Spam.
• Create a filter for specific email addresses and mark the option to Never Send to Spam.

See this Gmail Help post - Create rules to filter your emails